1. Field of the Invention
The present invention relates to a reading apparatus, an image forming apparatus and an image forming system.
2. Description of Related Art
Conventionally, there have been known image forming systems including electrophotographic image forming apparatuses and reading apparatuses, the electrophotographic image forming apparatuses providing toners to recording media such as sheets of paper and fixing the toners by heating or pressurizing the recording media to form images, and the reading apparatuses reading the images that were formed on the recording media by the image forming apparatuses. In such image forming systems, the image forming apparatuses form predetermined identification marks indicating the position, density and such like of images on recording media, the reading apparatuses read the predetermined identification marks formed on the recording media, and the reading results are analyzed to determine whether the image forming apparatuses are performing image formation appropriately.
Such image forming systems are provided with conveyance apparatuses which have conveyance rollers for conveying recording media on the upstream side and the downstream side in conveyance direction of reading positions by the reading apparatuses. Reading by the reading apparatuses is performed while conveying the recording media in a predetermined conveyance direction with the conveyance apparatuses. In order to suppress the load on the recording media, reading by the reading apparatuses is generally performed while conveying the recording media so as not to curve on conveyance paths which are linear when seen from the width direction orthogonal to the conveyance direction of the recording media (for example, see Japanese Patent Application Laid Open Publication No. 2012-94939).
However, the recording media on which images are formed have warpage and waviness caused by heat, pressure and such like which are applied to the recording media when the images are fixed. Thus, conventional image forming systems using linear conveyance paths have had a problem that reading cannot be performed appropriately since the heights of recording media at the reading positions by the reading apparatuses are changed due to the warpage and waviness. In addition, when the recording media are conveyed in the reading apparatus, the conveyance speeds by the conveyance rollers are also changed in some cases due to the variation in outside diameter of conveyance rollers and the change in outside diameter caused by the temperature change. Conventional image forming systems have had a problem that reading cannot be performed appropriately since the recording media become slack and the heights of recording media are changed at the reading positions by the reading apparatuses when the conveyance speeds of recording media on the upstream side of the reading positions by the reading apparatuses are relatively increased with respect to the conveyance speeds on the downstream side.